ParaViewServerManager: sort modules in topo-order
Proxy definitions can depend upon other proxy definitions. Within a module, they should be well-ordered already, but the module list passed in could be in an arbitrary order. To ensure that proxy definitions have a fighting chance being in the proper order, topologically sort modules when importing their XML files.
Fixes: #20317 (closed)
Tested that with this it works and without an error occurs.
Cc: @mwestphal
Backport: release